We propose to develop a method for the on-line measurement and manipulation of the sucking response of newborn human infants as a means of evaluating neonatal central nervous system functioning. Although sucking response has been previously used as an objective measure of newborn behavior, development of the proposed system will provide an interactive on-line system of significance for studying early growth, learning and maturation in the infant and with applicability to clinical use as well. This phase of the study involves development of the necessary methodology for analyzing the sucking response, converting the sucking measures into a mathematical form and developing and optimizing the software by which the computer will modify the experimental system for changing the various programs of reinforcement. The study will make use of data and techniques previously obtained in the dynamics and optimization from the engineering fields. A novel aspect of the work is to use computerized models simulating neonatal behavior based on available data as a tool in developing the methodology. A long term goal is to apply system to studies of neonatal development in such infant groups as premature and small for gestational age infants, and infants with asphyxia neonatorum.